Butyllithium

Endpoint summary

Additional information

n-Butyl lithium is pyrophoric and reacts violently with water/ air humidity to form butane and lithium hydroxide and butane is practically insoluble in water and readily volatilizes. Thus, aquatic toxicity studies with n-Buthyl lithium as such are scientifically not justified. Instead, lithium hydroxide (acute studies) was tested and tests with a lithium-salt (chronic study) were considered.

Short-term toxicity to fish

In this 96-h fish acute toxicity test with Zebrafish (Danio rerio) the 96h LC50 for Lithium hydroxide monohydrate based on mortality was determined to be 109 mg/L. The 96h LC10 was determined to be 96 mg/L and the NOEC 25 mg/L. All results are related the nominal concentrations. Based on the data, the LC50 calculated for n-Butyl lithium is 166 mg/L (i.e. above 100 mg/L). Thus, this result does not require any classification and labelling.

Long-term toxicity to fish

The purpose of the performed study was to evaluate the chronic toxicity of the test item lithium hydroxide monohydrate to early life stages (embryo, larvae and juveniles) of fish (Danio rerio) according to the OECD 210 guideline. Around 40 eggs per treatment / concentration level (2 replicates per treatment) were exposed in a semi static test to aqueous test media containing the test item for 34 days at a range of concentrations (based on a preliminary study) under defined conditions. Results showed that lithium hydroxide monohydrate had significant lethal effect on early life stages of Zebrafish (Danio rerio) at a concentration level of 24.35 mg/L (measured concentration). The observed effect was associated with larval/juvenile stages, but no significant effect was observed during the embryonic stage.

No significant sub lethal effects (hatching of the larvae, body weight, body length, deformities and abnormal behaviour) were observed in any concentration tested.

The following endpoints (34 days LOEC and NOEC) were calculated in the study:

The 34 d LOEC 24.35 mg test item/L

The 34 d NOEC 17.35 mg test item/L

Based on read across approach, the calculated LOEC and NOEC values for n-butyl lithium were 37.17 and 26.49 mg/L respectively.

The NOEC result does not lead to classification and labelling of n-butyl lithium for long-term aquatic toxicity (fish) according to Regulation (EC) 1272/2008 (CLP) and Directive 67/548/EC (DSD).

Short-term toxicity to aquatic invertebrates

Lithium hydroxide (purity 55.2 %) was tested for short term aquatic toxicity in Daphnia in an 48-hour static test according to EU Method C.2 and OECD Guideline 202. Without pH-adjustment the 48 hour EC 50-value was 19.1 mg/L. With pH-adjustment the 48-hour EC 50-value 34.3 mg/L. Based on the data, the 48 hour EC50 calculated for n-Butyl lithium is 51 mg/L without pH-adjustment and 91.7 mg/L with pH-adjustment.

Long-term to aquatic invertebrates

The NOEC for Lithium hydroxide determined in a reproduction test in daphnia was 4.0 mg/L and the LOEC was 8.0 mg/L. Based on the data, the NOEC calculated for n-Butyl lithium is 6.1 mg/L and the LOEC is 12.2 mg/L.

Although the 48 hour EC 50-value (daphnia) of n-Butyl lithium is greater than 10 mg/L but equal or lower than 100 mg/L (actually 51 mg/L without and 91.7 mg/L with pH adjustment), according to REGULATION (EC) No 1272/2008 and according to Directive 67/548/EC (DSD) criteria, n-Butyl lithium is not classified hazardous to the aquatic environment as the chronic toxicity NOEC is greater than 1 mg/L (actually 6.1 mg/L).

Toxicity to aquatic algae and cyanobacteria

Lithium hydroxide monohydrate was tested for toxicity to algae in a 72 h static test. The results showed an EC50 value of 153.44 mg/L and a NOEC of 10 mg/L, both based on growth rate. Based on the data, the 72 hour EC50 calculated for n-Butyl lithium is 234 mg/L and the NOEC is 15.3 mg/L.

As the 72 h ErC 50 for algae of n-Butyl lithium is greater 100 mg/L (actually 234 mg/L) and the NOEC is greater than 1 mg/L (actually 15.3 mg/L), n-Butyl lithium has not to be classified according to Regulation (EC) No 1272/2008 (CLP) and according to Directive 67/548/EC (DSD) criteria.

A supporting study with Lithium hydroxide anhydrous confirms that no classification and labeling is necessary. The results in this test showed an EC50 value of 5.76 mg/L and a NOEC of 0.68 mg/L, both based on growth rate. Based on the data, the 72 hour EC50 calculated for n-Butyl lithium is 15 mg/L and the NOEC is 1.8 mg/L. As the 72 h ErC 50 for algae of n-Butyl lithium is in the range of greater than 10 to lower than or equal to 100 mg/L (actually 15 mg/L) and the NOEC is higher than 1 mg/L (actually 1.8 mg/L), n-Butyl lithium has not to be classified according to Regulation (EC) No 1272/2008 (CLP) and according to Directive 67/548/EC (DSD) criteria. The study was regarded as supporting study as a study with Lithium hydroxide monohydrate is more representative for n-Butyl lithium in water due to strong hygroscopic character of the substance (i.e. Lithium covered by hydrate mantle).

Toxicity to microorganisms

The 3 hours EC20, EC50, and EC80 values for the test substance Lithium hydroxide in the Activated Sludge Respiration Inhibition Test were 114.3, 180.8, and 286.1 mg/L (based on measured inhibition rates), respectively. The EC10 value was calculated by linear regression to be 79.2 mg/L.

Based on this data, the 3 hours EC10, EC20, EC50, and EC80 values calculated for n-Butyl lithium in the Activated Sludge Respiration Inhibition Test are 211.8, 305.7, 483.6, and 765.2 mg/L, respectively.

Finally it should be stressed again that n-Butyl lithium may ignite spontaneously in air or on contact with water / air humidity and that therefore studies on ecotoxicity cannot be performed by standard methods. Spontaneous self-ignition occurred after a sample (n-Butyl lithium 90% added with 10% hexane) was poured into a cup used for flash point determination (see disregarded study section 4.11). Two reports on accidents resulting in death are also attached to demonstrate the extreme reactivity of these compound. Best measurements for occupational health and safety are required. All unnecessary risk has to be avoided. See section 4.23.